Motor

ABSTRACT

A motor includes a bus bar assembly including a bus bar, a wiring member, and a bus bar holder. The bus bar holder includes a main body portion, a bottom portion, and a first circuit board support portion. The wiring member includes a circuit board connection terminal electrically connected to the circuit board. The circuit board connection terminal includes a contact portion connected to the circuit board, and applies force to the circuit board through the contact portion. The first circuit board support portion is disposed at a region of the bottom portion to define a side at which the circuit board connection terminal is located when viewed from one direction. The first circuit board support portion and the contact portion are located at different positions when viewed from the one direction.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese PatentApplication No. 2014-201411 filed on Sep. 30, 2014 and Japanese PatentApplication No. 2015-109638 filed of May 29, 2015 and is a ContinuationApplication of PCT Application No. PCT/JP2015/076569 filed on Sep. 17,2015. The entire contents of each application are hereby incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a motor.

2. Description of the Related Art

In a conventional motor, a circuit board connection terminal is fixed toa circuit board of the motor by, for example, soldering.

In this case, the circuit board of the conventional motor may be fixedto a circuit body at a position spaced apart from a fixing portion fixedto an intermediate conductor. Therefore, when an impact is applied tothe motor, the position of the circuit board at the fixing portion maybe greatly changed. Therefore, the fixing portion may be damaged andconnection between the circuit board and the intermediate conductor maybecome unstable.

SUMMARY OF THE INVENTION

A motor according to a preferred embodiment of the present inventionincludes a rotor including a shaft which includes a center on a centeraxis extending in one direction; a stator enclosing the rotor androtating the rotor about the center axis; a first bearing which isdisposed at a first side in the one direction of the stator and supportsthe shaft; a second bearing which is disposed at a second side oppositeto the first side of the stator and supports the shaft; a cylindricalhousing holding the stator and the first bearing; a bus bar assemblyholding the second bearing, and allowing an end of the first side to belocated in the housing; a cover fixed to the housing to cover at least aportion of the second side of the bus bar assembly; a circuit boardwhich is disposed between the second bearing and the cover in the onedirection, and allows a surface of the second side to cross the onedirection, wherein the bus bar assembly includes a bus bar electricallyconnected to the stator; a wiring member electrically connecting anexternal power supply to the circuit board; and a bus bar holder holdingthe bus bar and the wiring member, the bus bar holder includes acylindrical main body portion including an opening at the second side, aconnector portion protruding from the main body portion toward aradially outer side of the center axis, and a bottom portion wideningfrom an inner surface of the main body portion toward the radially innerside, and a first circuit board support portion extending from thebottom portion toward the second inner side, and supporting the circuitboard from the first side, the cover covers the second side of theopening; and the wiring member includes an external power-supplyconnection terminal provided to the connector portion to be electricallyconnected to the external power-supply; and a circuit board connectionterminal electrically connected to the circuit board, wherein thecircuit board connection terminal includes a contact portion connectedto the circuit board, and applies force to the circuit board through thecontact portion in the direction from the second side to the first side,the first circuit board support portion is disposed at a region of thebottom portion to define a side at which the circuit board connectionterminal is located on the basis of the center axis when viewed from theone direction, and the first circuit board support portion and thecontact portion are disposed at different positions when viewed from theone direction.

The above and other elements, features, steps, characteristics andadvantages will become more apparent from the following detaileddescription of the preferred embodiments with reference to the attacheddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a motor according to apreferred embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view illustrating themotor according to a preferred embodiment of the present invention.

FIG. 3 is a plan view illustrating the motor according to a preferredembodiment of the present invention.

FIG. 4 is a perspective view illustrating a bus bar assembly accordingto a preferred embodiment of the present invention.

FIG. 5 is a plan view illustrating the bus bar assembly according to apreferred embodiment of the present invention.

FIG. 6 is a plan view illustrating another example of a bus bar assemblyaccording to a preferred embodiment of the present invention.

FIG. 7 is a plan view illustrating another example of a bus bar assemblyaccording to a preferred embodiment of the present invention.

FIG. 8 is a partially enlarged cross-sectional view illustrating anotherexample of a motor according to a preferred embodiment of the presentinvention.

FIG. 9 is a partially enlarged cross-sectional view illustrating anotherexample of a motor according to a preferred embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Motors according to preferred embodiments of the present invention willhereinafter be described with reference to the attached drawings.Further, the scope of the present invention is not limited to thefollowing preferred embodiments, but may be arbitrarily changed withinthe technical spirit of the present invention. To easily understand eachcomponent in the following drawings, an actual structures, and a scaleof each structure, the number of structures, etc., may be different.

In the drawings, an X-Y-Z coordinate system is provided as anappropriate three-dimensional (3D) orthogonal coordinate system. In theX-Y-Z coordinate system, a direction parallel to the axial direction(one direction) of a center axis J shown in FIG. 1 will hereinafter bereferred to as a Z-axis direction. A direction parallel to alongitudinal direction of a bus bar assembly 60 shown in FIG. 1, thatis, the left-and-right direction of FIG. 1, is referred to as an X-axisdirection. A direction parallel to a width direction of the bus barassembly 60, that is, a direction perpendicular to both the X-axisdirection and the Z-axis direction, is referred to as a Y-axisdirection.

In the following description, a positive side of the Z-axis direction(+Z side, a second side) will hereinafter be defined as a “rear side”and a negative side of the Z-axis direction (−Z side, a first side) willhereinafter be defined as a “front side.” It is to be understood thatthe descriptions of the rear side and the front side are used forexplanation only, and they do not limit location relation or directionof the actual motor, members, and the like. Unless otherwise explained,a direction parallel to the center axis J (Z-axis direction) is simplyreferred to as an “axial direction,” a radial direction having itscenter on the center axis J is simply referred to as a “radialdirection,” and a circumferential direction having its center on thecenter axis J, that is, the axial circumference of center axis J (ΘZdirection), is simply referred to as a “circumferential direction.”

Further, herein, descriptions such as being axially extended do not onlyrefer to a case of strictly being extended in the axial direction(Z-axis direction), but it may also include the other case of beingextended in a direction inclined at less than about 45° relative to theaxial direction, for example. Also, descriptions such as being radiallyextended do not only refer to a case of strictly being extended in theradial direction, that is, the direction perpendicular to the axialdirection (Z-axis direction), but it may also include a case of beingextended in a direction inclined at less than about 45° relative to theradial direction, for example.

FIG. 1 is a cross-sectional view illustrating a motor 10 according to apreferred embodiment of the present invention. FIG. 2 is across-sectional view illustrating a portion of the motor 10, and is apartially enlarged view of the motor shown in FIG. 1. FIG. 3 is a planview (XY plan view) illustrating some parts of the motor 10. A cover 22is omitted from FIG. 3.

The motor 10 according to the present preferred embodiment is abrushless motor. As illustrated in FIG. 1, the motor 10 includes ahousing 21, a cover 22, a rotor 30 including a shaft 31, a stator 40, afirst bearing 51, a second bearing 52, a controller 70, a bus barassembly 60, and a plurality of O-rings. The plurality of O-ringspreferably includes a front side O-ring 81 and a rear side O-ring 82.

The rotor 30, the stator 40, the first bearing 51, and the oil seal 80are accommodated into the housing 21. The housing 21 is opened towardthe rear side (+Z side). An end of the front side (−Z side) of the busbar assembly 60 is inserted into the opening of the housing 21. The busbar assembly 60 holds the second bearing 52. The first bearing 51 andthe second bearing 52 support both sides of the axial direction (Z-axisdirection) of the shaft 31.

The cover 22 covers at least a portion of the rear side (+Z side) of thebus bar assembly 60. The cover 22 is fixed to the housing 21. The cover22 preferably includes a cylindrical portion 22 a, a cover portion 22 b,a front surface 22 c of the cover, and a rear side flange portion 24.The controller 70 is located between the second bearing 52 and the cover22. The front side O-ring ring 81 is located between the bus barassembly 60 and the housing 21. The rear side O-ring 81 is locatedbetween the bus bar assembly and the cover 22. The above-mentionedcomponents will hereinafter be described in greater detail below.

The housing 21 is preferably a cylindrical or substantially cylindricalmember, and holds the stator 40 and the first bearing 51. In a preferredembodiment of the present invention, the housing 21 preferably has amulti-stepped cylindrical shape or a substantially multi-stepped shapewith open ends on both sides. In this preferred embodiment, a materialof the housing 21 is, for example, metal. In more detail, it ispreferred that a material of the housing 21 is, for example, aluminum,iron alloy, or the like.

The housing 21 preferably includes a front side flange portion 23, a busbar assembly insertion portion 21 a, a stator holding portion 21 b, afront bearing holding portion 21 c, and an oil seal holding portion 21d. The front side flange portion 23, the bus bar assembly insertionportion 21 a, the stator holding portion 21 b, the front bearing holdingportion 21 c, and the oil seal holding portion 21 d are disposed in adirection from the rear side (+Z side) to a front side (−Z side) alongthe axial direction(Z-axis direction). That is, in the housing 21, thefront side flange portion 23 is preferably disposed at a rearmost sideand the oil seal holding portion 21 d is preferably disposed at afrontmost side. Each of the bus bar assembly insertion portion 21 a, thestator holding portion 21 b, the front bearing holding portion 21 c, andthe oil seal holding portion 21 d has a concentric cylindrical orsubstantially cylindrical shape. A diameter of the above members arereduced in the order of the bus bar assembly insertion portion 21 a, thestator holding portion 21 b, the front bearing holding portion 21 c, andthe oil seal holding portion 21 d.

The front side flange portion 23 extends from the end of the rear side(+Z side) of the bus bar assembly insertion portion 21 a toward aradially outer side. That is, the housing 21 includes a housing flangeportion 23 at the end of the rear side. The bus bar assembly insertionportion 21 a encloses an end of a front side (−Z side) of the bus barassembly 60 from the radially outer side of the center axis J. In otherwords, at least a portion of the end of the front side (−Z side) of thebus bar assembly 60 is disposed in the bus bar assembly insertionportion 21 a. That is, the end of the front side of the bus bar assembly60 is disposed in the housing 21.

An outer surface of a stator 40 (preferably an outer surface of a coreback portion 41, to be described later) is fitted into an inner surfaceof the stator holding portion 21b.

Accordingly, the stator 40 is fixed to the housing 21. The front bearingholding portion 21 c holds the first bearing 51. In this preferredembodiment, the inner surface of the front bearing holding portion 21 cpreferably is fitted into the outer surface of the first bearing 51. Theoil seal 80 is held in the oil seat holding portion 21 d.

The rotor 30 preferably includes a shaft 31, a rotor core 32, and arotor magnet 33. The shaft 31 has its center on the center axis J whichextends in one direction (Z-axis direction). According to this exemplarypreferred embodiment, the shaft 31 is a cylindrical or substantiallycylindrical member. Further, the shaft 31 may be a solid member or as ahollow cylindrical member. The shaft 31 is rotatably supported aroundthe axis (in ±θZ direction) by the first bearing 51 and the secondbearing 52. The end of the front side (−Z side) of the shaft 31protrudes to the outside of the housing 21. In the oil seal holdingportion 21 d, the oil seal 80 is disposed around the axis of the shaft31.

The rotor core 32 is preferably a cylindrical or substantiallycylindrical member. The rotor core 32 is fixed to the shaft 31 whileenclosing the shaft 31 around the axis (in the θZ direction). In moredetail, the rotor core 32 preferably includes a through-hole whichpenetrates axially through the rotor core 32. At least a portion of theshaft 31 is disposed within the through-hole of the rotor core 32. Theshaft 31 is fixed to the rotor core 32 by, for example, press-fitting,adhesion, or the like. The rotor magnet 33 is fixed to an outer surfacealong an axis circumference of the rotor core 32. In more detail,according to this exemplary preferred embodiment, the rotor magnet 33preferably has an annular or substantially annular shape. The outersurface of the rotor core 32 faces the inner surface of the rotor magnet33. The rotor magnet 33 is fixed to the rotor core 32 by, for example,an adhesive, or the like. Further, the shape of the rotor magnet 33 isnot necessarily annular. The rotor magnet 33 may be defined by aplurality of magnets arranged on an outer circumferential surface of therotor core 32 in a circumferential direction. The rotor core 32 and therotor magnet 33 rotates integrally with the shaft 31.

The stator 40 preferably has a cylindrical or substantially cylindricalshape. The rotor 30 is located in the stator 40. In other words, thestator 40 encloses the rotor 30 around the axis (in the OZ direction).The rotor 30 may relatively rotate around the center axis J with respectto the stator 40. The stator 40 preferably includes a core back portion41, a plurality of teeth portions 42, a plurality of coils 43, and aplurality of bobbins 44. According to this exemplary preferredembodiment, the core back portion 41 and the teeth portion 42 is astacked steel plate in which a plurality of electromagnetic steel platesare stacked.

The core back portion 41 may have a cylindrical or substantiallycylindrical shape. Preferably, the shape of the core back portion 41 isconcentric with the shaft 31. The plurality of teeth portions 42 aredisposed on an inner surface of the core back portion 41. Each teethportion 42 extends from the inner surface of the core back portion 41toward a radially inner side (that is, toward the shaft 31). Preferably,the teeth portions 42 are arranged at equal or substantially equalintervals in the inner surface of the core back portion 41 in thecircumferential direction.

Preferably, the bobbin 44 is a cylindrical or substantially cylindricalmember. Each bobbin 44 is respectively mounted on one of the teethportions 42. Preferably, the bobbin is defined by at least two membersengaged from an axial direction. Each coil 43 is disposed in each bobbin44. Each coil 43 is provided preferably by winding a conductive wire 43a about a bobbin 44. Further, as the conductive wire 43 a, a circularwire or a flat wire is preferably used.

The first bearing 51 is disposed at a front side (−Z side) of the stator40. The first bearing 51 is held by the front bearing holding portion 21c. The second bearing 52 is disposed at the rear side (+Z side) oppositeto the front side (−Z side) of the stator 40. The second bearing 52 isheld by a rear bearing holding portion 65 of a bus bar holder 61 whichwill be described later.

The first bearing 51 and the second bearing 52 support the shaft 31.According to this preferred embodiment, each of the first bearing 51 andthe second bearing 52 is a ball bearing. However, the type of the firstbearing 51 and the second bearing 52 is not particularly limited to theabove bearing type. For example, different kinds of bearings such as asleeve bearing and a fluid hydraulic bearing may also be used. Further,the type of bearing of the first bearing 51 may be different from thatof the second bearing 52.

The oil seal 80 is preferably an annular or substantially annularmember. The oil seal 80 is mounted in the oil seal holding portion 21 daround the axis (in the θZ direction) of the shaft 31. In more detail,the oil seal 80 is disposed in the oil seal holding portion 21 d. An endof an axial lower portion of the shaft 31 penetrates through thethrough-hole of the oil seal 80. The oil seal 80 is disposed between theoil seal holding portion 21 d and the shaft 31. Therefore, the oil seal80 may prevent water, oil, etc., from infiltrating from a gap betweenthe oil seal holding portion 21 d and the shaft 31 into the housing 20.The oil seal 80 is preferably made of, for example, a resin material.However, a configuration and a material of the oil seal 80 are notlimited thereto, and therefore an oil seal of different kinds ofconfigurations and materials may also be used.

The controller 70 controls driving operations of the motor 10. Thecontroller 70 preferably includes the circuit board 71, a rotatingsensor 72, a sensor magnet holding member 73 a, and a sensor magnet 73b. That is, the motor 10 includes the circuit board 71, the rotationsensor 72, the sensor magnet holding member 73 a, and the sensor magnet73 b.

The circuit board 71 is disposed on an extending line of the rear side(+Z side) of the shaft 31. The circuit board 71 is disposed between thesecond bearing 52 and the cover 22 in the axial direction (Z-axisdirection). The circuit board 71 includes a circuit board rear surface71 a located at the rear side and a circuit board front surface 71 blocated at the front side (−Z side). The circuit board rear surface 71 aand the circuit board front surface 71 b define a main surface of thecircuit board 71. That is, the circuit board front surface 71 b and thecircuit board rear surface 71 a intersect with the center axis (Z-axis).In preferred embodiment, the main surface of the circuit board 71 ispreferably orthogonal or substantially orthogonal to the center axis J(or Z-axis). The circuit board rear surface 71 a faces the cover frontsurface 22 c.

As illustrated in FIG. 3, the circuit board 71 is supported, from thefront side (−Z side), by the first circuit board support portions 67 aand 67 b and the second circuit board support portion 67 c (describedlater). A printed wiring (not shown) is preferably disposed in at leastone side of the main surface of the circuit board 71. A circuit boardconnection terminal 95 (described later) is connected to the circuitboard rear surface 71 a. The circuit board 71 outputs, for example, amotor driving signal, etc.

As illustrated in FIG. 2, the sensor magnet holding member 73 a is anannular or substantially annular member. A hole at a center of thesensor magnet holding member 73 a is fitted with a small diameter of theend of the rear side (+Z side) of the shaft 31. Accordingly, theposition of the sensor magnet holding member 73 a is determined on thebasis of the shaft 31. Preferably, the sensor magnet holding member 73 ais fixed to the shaft 31 by press-fitting, adhesion, etc. The sensormagnet holding member 73 a may rotate along with the shaft 31.

The sensor magnet 73 b preferably has an annular or substantiallyannular shape. An N pole and an S pole of the sensor magnet 73 b arealternately disposed in the circumferential direction. The sensor magnet73 b is fitted on an outer circumferential surface of the sensor magnetholding member 73 a. In more detail, at least a portion of the sensormagnet 73 b comes in contact with the outer circumferential surface ofthe sensor magnet holding member 73 a. Therefore, the sensor magnet 73 bis fixed to the sensor magnet holding member 73 a. As a result, thesensor magnet 73 b is disposed at the circumference (±θZ direction) ofthe shaft 31 at the rear side (+Z side) of the second bearing 52 suchthat the sensor magnet 73 b is able to rotate along with the shaft 31.

At least one rotation sensor 72 is preferably mounted on the frontsurface 71 b of the circuit board. The rotation sensor faces the sensormagnet 73 b in the axial direction (Z-axis direction). The rotationsensor 72 detects the position of the rotor depending on a change inmagnetic flux of the sensor magnet 73 b. Although not illustrated,according to the preferred embodiment, three rotation sensors 72 arepreferably disposed on, for example, the front surface 71 b of thecircuit board. Further, as the rotation sensor 72, for example, a halldevice, etc., is used.

FIGS. 4 and 5 are views illustrating the bus bar assembly 60. FIG. 4 isa perspective view. FIG. 5 is a plan view. The bus bar assembly 60supplies a driving current from the external power source to the stator40. As illustrated in FIGS. 1 to 5, the bus bar assembly 60 preferablyincludes a bus bar holder 61, at least one bus bar 91, and a wiringmember 92. In addition, in preferred embodiment, the bus bar assembly 60includes a plurality of bus bars 91.

The bus bar holder 61 is preferably defined by a holder made of resin.Preferably, a material of the bus bar holder is an electricallyinsulating resin. The bus bar holder 61 holds the bus bar 91 and thewiring member 92. As illustrated in FIG. 1, a rear side (+Z side) of thebus bar holder 61 is accommodated in the cylindrical portion 22 a. Inthis preferred embodiment, the bus bar holder 61 is press-fitted intothe cylindrical portion 22a. At least a portion of a front side (−Zside) of the bus bar holder 61 is accommodated in the bus bar assemblyinsertion portion 21 a of the housing 21.

As long as a material making the bus bar holder 61 has an insulationproperty, any material may be used without being specially limited. Thebus bar holder 61 preferably is manufactured as a single monolithicmember by, for example, injection molding. As illustrated in FIGS. 4 and5, the bus bar holder 61 includes a main body portion 62, a connectorportion 63, a connection terminal holding portion 64, a rear bearingholding portion 65, and connection portions 66 a, 66 b, 66 c, and 66 d.

As illustrated in FIGS. 1 and 4, the main body portion 62 preferably hasa cylindrical or substantially cylindrical shape enclosing the centeraxis J in the circumferential direction (θZ direction). The main bodyportion 62 includes an opening 62 a at the rear side (+Z side) thereof.The main body portion 62 preferably encloses the end of the rear side ofthe rotor 30 and the end of the rear side of the stator 40 in thecircumferential direction. That is, a portion of the rear side of therotor 30 and the stator 40 is located in the inner side of the frontside (−Z side) of the main body portion 62.

A rear surface 62 c of the main body portion is preferably provided witha groove portion 62 f. The groove portion 62 f is provided along thecontour of the main body portion 62 enclosing the opening 62 a. A rearside O-ring 82 is fitted into the groove portion 62 f. As illustrated inFIG. 4, the front side (−Z side) of the outer surface 62 d of the mainbody portion 62 is provided with an O-ring holding portion 62 e. Asillustrated in FIG. 1, the front side O-ring 81 is fitted into theO-ring holding portion 62 e.

As illustrated in FIGS. 4 and 5, the main body portion preferablyincludes an arc portion 68 a and a connector connection portion 68 b. Asillustrated in FIG. 5, the shape of a cross section (XY cross-section)perpendicular to the center axis J of the arc portion 68 a and the shapeof a plan view (XY plan view) is an arc shape concentric with the rearbearing holding portion 65. Preferably, a central angle of the arc shapemay be φ240° or higher, for example. In this preferred embodiment, thearc portion 68 a is preferably press-fitted into the cylindrical portion22 a of the cover 22.

As illustrated in FIGS. 4 and 5, the connector connection portion 68 bis connected to the connector portion 63. The connector connectionportion 68 b is connected to both ends of the arc portion 68 a. Theconnector connection portion 68 b protrudes toward the connector portion63 (+_X side).

The connector portion 63 is a portion connected to external power supply(not shown). The connector portion 63 has a cylindrical shape. Theconnector portion 63 preferably has a rectangular parallelepiped orsubstantially rectangular parallelepiped shape. The connector portion 63extends from a portion of the outer surface of the connector connectionportion 68 b to the radially outer side (+X side) of the center axis J.The connector portion 63 includes an opening at the radially outer side(+X side). That is, the connector portion 63 protrudes from the mainbody portion 62 toward the radially outer side of the center axis J. Asillustrated in FIG. 1, the entirety of the connector portion 63 isexposed outside the cover 22.

As illustrated in FIG. 1, the connector portion 63 preferably includesan opening 63 a for a power supply opened toward one side (+X side)disposed in a longitudinal direction of the bus bar holder 61. A bottomsurface of the power-supply opening 63 a is provided with the bus bar 91and an external power-supply connection terminal 94 to be describedlater. The bus bar 91 and the external power-supply connection terminal94 protrude from the bottom surface of the power-supply opening 63 atoward one side (+X side) disposed in the longitudinal direction of thebus bar holder 61.

As illustrated in FIGS. 4 and 5, the connection terminal holding portion64 preferably has a rectangular parallelepiped or substantiallyrectangular parallelepiped shape. The connection terminal holdingportion 64 protrudes toward the radially inner side from the innersurface 62 b of the main body portion. In more detail, as illustrated inFIG. 5, the connection terminal holding portion 64 extends from theinner surface of the connector connection portion 68 b in the direction(−X direction) opposite to the direction in which the connector portion63 extends. The holding portion rear surface 64 b is located at thefront side ahead of the circuit board rear surface 71 a. The holdingportion rear surface 64 b is located at the front side ahead of the mainbody rear surface 62 c of the rear side of the main body portion 62.

The rear bearing holding portion 65 is disposed at the radially innerside of the main body portion 62. As illustrated in FIG. 2, the rearbearing holding portion 65 holds the second bearing 52.

As illustrated in FIG. 5, the connection portions 66a, 66 b, 66 c, and66 d connect the main body portion 62 to the rear bearing holdingportion 65 disposed in the main body portion 62. The connection portions66 a-66 d are positioned at the circumference of the rear bearingholding portion 65 while being spaced apart from each other at equal orsubstantially equal intervals along the circumferential direction.

Gaps 66 e, 66 f, 66 g, and 66 h are provided among the connectionportions 66 a-66 d neighboring with each other in the circumferentialdirection. That is, gaps 66 e, 66 f, 66 g, and 66 h are provided betweenthe rear bearing holding portion 65 and the main body portion 62. Thegap 66 e is defined by the connection portion 66 a, the connectionportion 66 b, the main body portion 62, and the rear bearing holdingportion 65. The gap 66 f is defined by the connection portion 66 b, theconnection portion 66 c, the main body portion 62, and the rear bearingholding portion 65. The gap 66 g is defined by the connection portion 66c, the connection portion 66 d, the main body portion 62, and the rearbearing holding portion 65. The gap 66 h is defined by the connectionportion 66 d, the rear bearing holding portion 65, the connectionportion 66 a, the connection terminal holding portion 64, and the mainbody portion 62.

In a plan view, the position of the gap 66 e is a position includingcoil connection portions 91 a and 91 b to be described later. In a planview, the position of the gap 66 f is a position including coilconnection portions 91 c and 91 d to be described later. In a plan view,the position of the gap 66 g is a position including coil connectionportions 91 e and 91 f to be described later. In a plan view, theposition of the gap 66 h is a position including a circuit boardconnection terminal 95 to be described later. In a plan view, theappearance of the gap 66 h is a rectangular or substantially rectangularshape.

As illustrated in FIGS. 4 and 5, the bottom portion 61 a preferablyincludes a connection terminal holding portion 64, a rear bearingholding portion 65, and connection portions 66 a-66 d. That is, the busbar holder 61 includes the bottom portion 61 a. The bottom portion 61 aextends from the main body inner surface 62 b toward the radially innerside.

As illustrated in FIG. 3, the bottom portion 61 a is preferably dividedinto two regions by a division line C1. The division line C1 isperpendicular or substantially perpendicular to the protrusion direction(X-axis direction) and the axial direction (Z-axis direction) of theconnector portion 63, and crosses the center axis J. Further, in thefollowing description, the direction parallel or substantially parallelto the direction of the division line C1 will hereinafter be referred toas a division-line direction (Y-axis direction).

In the bottom portion 61 a, a region of a specific side (+X side) inwhich the circuit board connection terminal 95 of the division line C1is provided when viewed from the plan view (XY plan view) willhereinafter be referred to as a first region AR1. That is, in the bottomportion 61 a, the first region AR1 is a region of the side (+X side) inwhich the circuit board connection terminal 95 is provided on the basisof the center axis J when viewed from the axial direction (Z-axisdirection).

In the bottom portion 61 a, a region of the other side (−X side)opposite to the above side at which the circuit board connectionterminal 95 of the division line C1 is provided when viewed from theplan view (XY plan view) will hereinafter be referred to as a secondregion AR2. That is, in the bottom portion 61 a, the second region AR2is a region of the side (−X side) opposite to the above side at whichthe circuit board connection terminal 95 is provided on the basis of thecenter axis J when viewed from the axial direction (Z-axis direction).

First circuit board support portions 67 a and 67 b, a second circuitboard support portion 67 c, first protrusion portions 69 a and 69 b,second protrusion portions 69 c and 69 d, and bus bar holder convexportions 69 e and 69 f are preferably disposed at the surface of therear side (+Z side) of the bottom portion 61 a. That is, the bus barholder 61 includes the first circuit board support portions 67 a and 67b, the second circuit board support portion 67 c, the two firstprotrusion portions 69 a and 69 b, the second protrusion portions 69 cand 69 d, and the bus bar holder convex portions 69 e and 69 f. Further,in the following description, the second protrusion portions 69 c and 69d may also be referred to as third circuit board support portions 69 cand 69 d.

As illustrated in FIG. 4, the first circuit board support portions 67 aand 67 b extend from the bottom portion 61 a toward the rear side (+Zside). As illustrated in FIG. 2, the first circuit board support portion67 b supports the circuit board 71 from the front side (−Z side). Thatis, the end of the rear side of the first circuit board support portion67 b contacts the circuit board front surface 71 b. The end of the rearside of the first circuit board support portion 67 b is also able to beapplied to the first circuit board support portion 67 a.

As illustrated in FIG. 3, the first circuit board support portions 67 aand 67 b is disposed in the first region AR1. The first circuit boardsupport portions 67 a and 67 b and a contact portion 95 e to bedescribed later are arranged at different positions when viewed from theaxial direction (Z-axis direction). In the present preferred embodiment,the first circuit board support portions 67 a and 67 b are disposedbetween the shaft 31 and the contact portion 95 e in the radialdirection.

As illustrated in FIG. 5, in the present preferred embodiment, the firstcircuit board support portions 67 a and 67 b are preferably disposed atthe surface of the rear side (+Z side) of the rear bearing holdingportion 65 from among elements of the bottom portion 61 a. The firstcircuit board support portions 67 a and 67 b are disposed at the edge ofthe center axis J (−X side) of a gap 66 h.

As illustrated in FIG. 3, the first circuit board support portion 67 aand the first circuit board support portion 67 b are preferably arrangedalong the division-line direction (Y-axis direction). In thedivision-line direction, the first circuit board support portion 67 a isarranged at the same position as the end of the +Y side of theconnection terminal holding portion 64. In the division-line direction,the first circuit board support portion 67 b is provided at the sameposition as the end of the −Y side of the connection terminal holdingportion 64.

A portion of the first circuit board support portion 67 a is preferablydisposed at one side (+Y side) of the plurality of contact portions 95 ein the division-line direction (Y-axis direction), i.e., in thearrangement direction (the predetermined direction) of the contactportion 95 e of the circuit board connection terminal 95, to bedescribed later. A portion of the first circuit board support portion 67b is preferably disposed at the other side (−Y side) of the plurality ofcontact portions 95 e in the division-line direction.

In FIG. 3, the plan view shape of the first circuit board supportportions 67 a and 67 b preferably is a rectangular or substantiallyrectangular shape, for example. The plan view (XY plan view) shape ofthe first circuit board support portions 67 a and 67 b is not limited tothe above shapes. The plan view (XY plan view) shape of the firstcircuit board support portions 67 a and 67 b may be, for example, acircular or substantially circular shape, a rectangular or substantiallyrectangular shape, and a polygonal shape. The first circuit boardsupport portions 67 a and 67 b extend along the division-line direction(Y-axis direction). That is, the first circuit board support portions 67a and 67 b extend along the arrangement direction (the predetermineddirection) of the contact portion 95 e of the circuit board connectionterminal 95 to be described later.

As illustrated in FIG. 4, the second circuit board support portion 67 cextends from the bottom portion 61 a to the rear side (+Z side). Asillustrated in FIG. 2, the second circuit board support portion 67 cpreferably supports the circuit board 71 from the front side (−Z side).That is, the end of the rear side of the second circuit board supportportion 67 c contacts the circuit board front surface 71 b.

As illustrated in FIG. 3, the second circuit board support portion 67 cis located in the second region AR2. As illustrated in FIG. 5, thesecond circuit board support portion 67 c is located at the surface ofthe rear side (+Z side) of the rear bearing support portion 65 fromamong elements of the bottom portion 61 a. In FIG. 3, the plan viewshape of the second circuit board support portion 67 c is preferably ashape that extends in the circumferential direction. The plan view (XYplan view) shape of the second circuit board support portion 67 c is notlimited to the above-mentioned shape in the same manner as in the firstcircuit board support portions 67 a and 67 b. The second circuit boardsupport portion 67 c is preferably located at the same position as thecenter portion of the connection terminal holding portion 64 in thedivision-line direction (Y-axis direction).

As illustrated in FIG. 4, the first protrusion portions 69 a and 69 bextend from the bottom portion 61 a to the rear side (+Z side). Asillustrated in FIG. 3, the first protrusion portions 69 a and 69 b areprovided along the division-line direction (Y-axis direction). The firstprotrusion portions 69 a and 69 b are preferably located in the firstregion AR1. As illustrated in FIG. 5, the first protrusion portion 69 ais located at the connection portion 66 a from among elements of thebottom portion 61 a. In the present preferred embodiment, the firstprotrusion portion 69 b is located at the connection portion 66 d fromamong elements of the bottom portion 61 a.

The radial distance between the first protrusion portion 69 a and thecenter axis J is longer than the radial distance between the end of theradially inner side of the coil connection portions 91 a-91 f (describedlater) and the center axis J. That is, the first protrusion portion 69 ais preferably located at the radially outer side ahead of the end of theradially inner side of the coil connection portions 91 a-91 f. Whenviewed from the axial direction (Z-axis direction), the first protrusionportion 69 a preferably overlaps with at least a portion of the coilconnection portions 91 a-91 f in the circumferential direction. Theabove-mentioned description may also be equally applied to the firstprotrusion portion 69 b. As illustrated in FIG. 3, the first protrusionportions 69 a and 69 b are inserted into a notch provided to the circuitboard 71.

As illustrated in FIG. 2, the end of the rear side (+Z side) of thefirst protrusion portion 69 b is disposed at the rear side ahead of thecircuit board 71. In the first protrusion portion 69 b, a portionprotruding toward the rear side ahead of the circuit board rear surface71 a is made molten by heat such that the protruding portion isdeposited on the circuit board rear surface 71 a. For example, thedeposited portion of the first protrusion portion 69 b preferably has ahemispheric or substantially hemispheric shape. The above-mentioneddescription is also equally applied to the first protrusion portion 69a. Therefore, the first protrusion portions 69 a and 69 b are fixed tothe circuit board 71. As a result, the first protrusion portions 69 aand 69 b support the circuit board 71 from the rear side.

As illustrated in FIG. 4, the second protrusion portions 69 c and 69 dextend from the bottom portion 61 a toward the rear side (+Z side). Asillustrated in FIG. 3, the second protrusion portions 69 c and 69 d areprovided along the division-line direction (Y-axis direction). Thesecond protrusion portions 69 c and 69 d are preferably located in thesecond region AR2. As illustrated in FIG. 5, the second protrusionportions 69 c and 69 d are preferably located in the rear bearingholding portion 65 from among elements of the bottom portion 61 a. Asillustrated in FIG. 3, the second protrusion portions 69 c and 69 d areinserted into the notch provided to the circuit board 71.

As illustrated in FIG. 2, the end of the rear side (+Z side) of thesecond protrusion portion 69 d is preferably located at the rear sideahead of the circuit board 71. In the second protrusion portion 69 d, aportion protruding toward the rear side ahead of the circuit board rearsurface 71 a is made molten by heat such that the protruding portion isdeposited on the circuit board rear surface 71 a. That is, the secondprotrusion portion 69 d is deposited on the circuit board rear surface71 a. For example, the deposited portion of the second protrusionportion 69 d preferably has a hemispheric or substantially hemisphericshape. The above-mentioned description is also equally applied to thesecond protrusion portion 69 c. Therefore, the second protrusionportions 69 c and 69 d are fixed to the circuit board 71. As a result,the second protrusion portions 69 c and 69 d support the circuit board71 from the rear side.

As illustrated in FIG. 4, the bus bar holder convex portions 69 e and 69f extend from the bottom portion 61 a to the rear side (+Z side). Asillustrated in FIG. 3, the bus bar holder convex portions 69 e and 69 fare provided along the division-line direction. In the present preferredembodiment, the bus bar holder convex portions 69 e and 69 f arepreferably located in the second region AR2. The end of the rear side ofthe bus bar holder convex portions 69 e and 69 f is inserted into a holeportion provided to the circuit board 71.

The bus bar 91 is a thin plate-shaped member made of an electricallyconductive material (for example, metal, etc.). The bus bar 91 isdirectly or indirectly electrically connected to the stator 40. Thedriving current is supplied from external power supply or the like tothe stator 40 through the bus bar 91. Although not shown in thedrawings, according to this preferred embodiment, the plurality of busbars 91 is mounted to the stator 40. For example, if the motor is athree-phase motor, at least three bus bars 91 are mounted to the stator40. In addition, according to a difference in coil wiring methods, thenumber of bus bars 91 may be changed to, for example, 4 or higher. Eachbus bar 91 is disposed in the bus bar holder 61. One end of the bus bar91 is exposed outside the cover 22. For example, the external powersupply is connected to one end of the bus bar 91 exposed outside thecover 22.

As illustrated in FIG. 5, the plurality of bus bars 91 include coilconnection portions 91 a, 91 b, 91 c, 91 d, 91 e, and 91 f. The coilconnection portions 91 a-91 f are disposed at the other end of theplurality of bus bars 91. The coil connection portions 91 a-91 fpreferably protrude from the inner surface 62 b of the main bodyportion. In more detail, the coil connection portions 91 a-91 f protrudefrom the inner surface of the arc portion 68 a of the inner surface 62 bof the main body portion toward the radially inner side. The coilconnection portion 91 c shown in FIG. 2 is electrically connected to thecoil 43 through a connection member (not shown). Therefore, the bus bar91 is electrically connected to the stator 40. In the above description,the coil connection portions 91 a, 91 b, 91 d-91 f are preferablyidentical in structure to the coil connection portion 91 c.

The wiring member 92 is fixed to the bus bar holder 61. A portion of thewiring member 92 is preferably embedded in the bus bar holder 61. Thewiring member 92 electrically connects the external power supply (notshown) to the circuit board 71. In the present preferred embodiment,several wiring members 92 are provided. In other words, the bus barassembly 60 preferably includes a plurality of wiring members 92. Thewiring member 92 includes the external power-supply connection terminal94 and the circuit board connection terminal 95. The externalpower-supply connection terminal 94 and the circuit board connectionterminal 95 are exposed from the bus bar holder 61.

The external power-supply connection terminal 94 is provided in theconnector portion 63. The external power-supply connection terminal 94protrudes from the bottom surface of the power-supply opening 63 a. Theexternal power-supply connection terminal 94 is electrically connectedto the external power supply (not shown).

As illustrated in FIG. 2, the circuit board connection terminal 95protrudes from the holding portion inner surface 64 a. The circuit boardconnection terminal 95 preferably includes a first connection portion 95a, a first extension portion 95 b, a second connection portion 95 c, asecond extension portion 95 d, and a contact portion 95 e.

The first connection portion 95 a protrudes from the holding portioninner surface 64 a toward the radially inner side. That is, the firstconnection portion 95 a extends from the connection terminal holdingportion 64 toward the radially inner side. The first connection portion95 a is located at the radially outer side ahead of the circuit board71.

The first extension portion 95 b extends from the first connectionportion 95 a toward the rear side (+Z side). In more detail, the firstextension portion 95 b extends from the end of the radially inner sideof the first connection portion 95 a toward the rear side. The firstextension portion 95 b extends to the rear side of the circuit board 71.That is, the end of the rear side of the first extension portion 95 b islocated at the rear side ahead of the circuit board rear surface 71 a.

The second connection portion 95 c extends from the first extensionportion 95 b in the radial direction. In the present preferredembodiment, the second connection portion 95 c extends from the firstextension portion 95 b toward the radially inner side. In more detail,the second connection portion 95 c extends from the end of the rear side(+Z side) of the first extension portion 95 b toward the radially innerside.

The second extension portion 95 d extends from the second connectionportion 95 c toward the axial direction (Z-axis direction). In thepresent preferred embodiment, the second extension portion 95 d extendsfrom the second connection portion 95 c to the front side (−Z side). Inmore detail, the second extension portion 95 d extends from the end ofthe radially inner side of the second connection portion 95 c toward thefront side. The end of the front side of the second extension portion 95d is located at the rear side (+Z side) ahead of the end of the frontside of the first extension portion 95 b. The second extension portion95 d is connected to the contact portion 95 e.

The contact portion 95 e extends from the end of the front side (−Zside) of the second extension portion 95 d toward the radially innerside. The contact portion 95 e is preferably located at the end of theradially inner side of the circuit board connection terminal 95. Thecontact portion 95 e preferably has a flat plate shape, and includes acontact surface 95 f parallel or substantially parallel to the circuitboard rear surface 71 a at the front side.

The contact surface 95 f contacts the circuit board rear surface 71 a.For example, the contact portion 95 e is preferably fixed to the circuitboard 71 by soldering (not shown). As a result, the contact portion 95 eis connected to the circuit board 71. That is, the circuit boardconnection terminal 95 is electrically connected to the circuit board 71through soldering. Thus, the wiring member 92 is also electricallyconnected to the circuit board 71.

As illustrated in FIG. 3, the contact portions 95 e of the plurality ofwiring members 92 are provided on the circuit board rear surface 71 a ina predetermined direction. In the present preferred embodiment, thecontact portions 95 e are preferably provided along the division-linedirection (Y-axis direction).

The circuit board connection terminals 95 apply force to the circuitboard 71 in the direction from the rear side (+Z side) to the front side(−Z side) through the contact portions 95 e. That is, under thecondition that the circuit board 71 is separated, the contact surface 95f at the contact portion 95 e is disposed at the front side ahead of thecircuit board rear surface 71 a in the axial direction (Z-axisdirection).

Under the condition that the circuit board connection terminal 95 isconnected to the circuit board 71, for example, the circuit boardconnection terminal 95 is elastically deformed in the axial direction(Z-axis direction). As an example, the first extension portion 95 bextends in the axial direction, resulting in increase of the axialthickness. The second extension portion 95 d is reduced in size in theaxial direction, resulting in reduction of the axial thickness of thesecond extension portion 95 d.

As illustrated in FIG. 5, in the circumferential direction (ΘZdirection) of the center axis J, the position of the circuit boardconnection terminal 95 is preferably different from those of the coilconnection portions 91 a-91 f.

As illustrated in FIG. 1, the front side O-ring 81 is disposed in thehousing 21. The front side O-ring 81 is fixed to the O-ring holdingportion 62 e of the bus bar holder 61. The front side O-ring 81 contactsthe inner surface of the housing 21 and the outer surface of the mainbody portion 62 over the circumference. That is, the front side O-ring81 contacts the main body portion 62 and the housing 21 over thecircumference. Stress generated from the inner surface of the bus barassembly insertion portion 21 a is loaded on the front side O-ring 81.

The rear side O-ring 82 is disposed in the cover 22. The rear sideO-ring 82 is fitted into the groove portion 62 f. The cover 22, to bedescribed later, includes a cover front surface 22 c at the front side(−Z side) of the cover portion 22 b. The entire circumference of therear side O-ring 82 contacts the cover front surface 22 c, to bedescribed later. Stress generated from the cover front surface 22 c isloaded on the rear side O-ring 82.

In preferred embodiment, the front side O-ring 81 and the rear sideO-ring 82 are preferably made of, for example, resin including siliconrubber or the like. In this case, the front side O-ring 81 and the rearside O-ring 82 are preferably manufactured by, for example, machiningelongated silicon rubber having a round cross section in a ring shape.However, a configuration and a material of the front side O-ring 81 andthe rear side O-ring 82 are not limited thereto.

The cover 22 is attached to the rear side (+Z side) of the housing 21. Amaterial of the cover 22 is preferably, for example, metal. In moredetail, as the material of the cover 22, for example, aluminum or aniron alloy such as SUS is used. As described above, the cover 22includes a cylindrical portion 22 a, a cover portion 22 b, a cover frontsurface 22 c, and a rear side flange portion 24.

The cylindrical portion 22 a is opened toward the front side (−Z side).The cylindrical portion 22 a encloses the bus bar assembly 60 from theradially outer side of the center axis J. In more detail, thecylindrical portion 22 a encloses the end of the rear side (+Z side) ofthe main body portion 62 from the radially outer side of the center axisJ. In other words, at least a portion of the end of the rear side (+Zside) of the main body portion 62 is disposed in the cylindrical portion22 a. The cylindrical portion 22 a is connected to the end of the rearside (+Z side) of the bus bar assembly insertion portion 21 a throughthe front side flange portion 23 and the rear side flange portion 24.

The cover portion 22 b is connected to the end of the rear side (+Zside) of the cylindrical portion 22 a. In this preferred embodiment, thecover portion 22 b preferably has a plate shape. The cover portion 22 bpreferably includes the cover front surface 22 c at the front side (−Zside). The cover portion 22 b closes the opening 62 a. That is, thecover portion 22 b covers the rear side of the opening 62 a. The coverfront surface 22 c contacts the entire circumference of the rear sideO-ring 82. Therefore, the cover 22 indirectly contacts the main bodyrear surface 62 c through the rear side O-ring 82 over a circumferenceof the opening 62 a.

The rear side flange portion 24 extends from the end of the front side(−Z side) of the cylindrical portion 22 a toward the radially outerside. At least a portion of the front side flange portion 23 and atleast a portion of the rear side flange portion 24 are bonded to eachother while overlapping with each other, such that the housing 21 isbonded to the cover 22.

For example, the external power supply is connected to the motor 10through the connector portion 63. The bus bar 91 protrudes from thebottom surface of the power-supply opening 63 a. The connected externalpower supply is electrically connected to the bus bar 91 and the wiringmember 92. Therefore, the driving current is supplied from the externalpower supply to the coil 43 and the rotation sensor 72 through the busbar 91 and the wiring member 92. The rotation sensor 72 detects themagnetic flux of the rotor magnet. The driving current supplied to thecoil 43 is controlled depending on the rotating position of the rotor 30calculated based on, for example, the detected magnetic flux of therotor magnet. When the driving current is supplied to the coil 43, amagnetic field is generated in the coil 43. In other words, when thedriving current is supplied to the coil 43, a torque is generatedbetween the rotor 30 and the stator 40. With this torque, the rotor 30having the shaft 31 rotates. By doing so, the motor 10 obtains arotational driving force.

The circuit board connection terminal 95 applies force to the circuitboard 71 through the contact portion 95 e in a direction from the rearside to the front side. Therefore, the circuit board connection terminal95 is able to be strongly fixed to the circuit board 71. In addition,although there is a deviation in thickness (i.e., a deviation in theaxial thickness) of the circuit board rear surface 71 a, any lack ofcontact between the circuit board 71 and the circuit board connectionterminal 95 is able to be significantly reduced or prevented.

The first circuit board support portions 67 a and 67 b are preferablylocated in the first region AR1. Therefore, the first circuit boardsupport portions 67 a and 67 b support the circuit board 71 in contactlocations between the circuit board 71 and the circuit board connectionterminal 95 (i.e., in the vicinity of the contact portion 95 e).Therefore, when impact is applied to the motor 10, the displacement ofthe circuit board 71 is able to be significantly reduced or prevented,in connection locations between the circuit board 71 and the contactportion 95 e. Therefore, a connection portion between the circuit board71 and the contact portion 95 e, for example, the soldered portion, isable to be prevented from being damaged. As a result, an unstableelectrical connection between the circuit board 71 and the circuit boardconnection terminal 95 is able to be prevented from occurring.

When viewed from the axial direction, the first circuit board supportportions 67 a and 67 b are disposed at a position different from that ofthe contact portion 95 e. Therefore, when the contact portion 95 e isconnected to the circuit board 71, heat caused by soldering, forexample, is not easily applied to the first circuit board supportportions 67 a and 67 b. Therefore, the above-mentioned operationprevents the first circuit board support portions 67 a and 67 b frombeing deformed by heat. As a result, the circuit board 71 is stablysupported by the first circuit board support portions 67 a and 67 b.

The second circuit board support portion 67 c is preferably located inthe second region AR2. Accordingly, the circuit board 71 is supported inthe first region AR1 and the second region AR2 on the basis of thecenter axis J by the first circuit board support portions 67 a and 67 band the second circuit board support portion 67 c. Therefore, accordingto the present preferred embodiment, the circuit board 71 is more stablysupported.

The first circuit board support portions 67 a and 67 b are preferablylocated between the shaft 31 and the contact portion 95 e in the radialdirection. Therefore, the circuit board 71 is able to be easily insertedin the direction from the first circuit board support portions 67 a and67 b and the contact portion 95 e to the front side of the contactportion 95 e. As a result, according to the present preferredembodiment, the circuit board 71 is easily attached.

If force is applied to the front side of the circuit board 71 throughthe contact portion 95 e, a rotational moment could occur in the circuitboard 71 using the first circuit board support portions 67 a and 67 b asa leverage point. As a result, there is a high possibility that aposture of the circuit board 71 becomes unstable.

In contrast, according to the present preferred embodiment, the secondprotrusion portions 69 c and 69 d are disposed in the second region AR2.The first circuit board support portions 67 a and 67 b are disposedbetween the shaft 31 and the contact portion 95 e. Therefore, arotational moment caused by the contact portion 95 e is opposed by thesecond protrusion portions 69 c and 69 d due to a reverse rotationalmoment which occurs using the first circuit board support portions 67 aand 67 b as a leverage point. Therefore, according to the presentpreferred embodiment, the circuit board 71 is able to be stablysupported.

The second protrusion portions 69 c and 69 d are preferably located onthe circuit board rear surface 71 a, such that the circuit board 71 isable to be more strongly fixed.

The circuit board connection terminal 95 preferably includes a firstextension portion 95 b extending toward the rear side. Therefore, sincethe first extension portion 95 b is elastically deformed in the axialdirection, force is able to be applied to the circuit board 71 in thedirection from the rear side to the front side.

The circuit board connection terminal 95 preferably includes a secondextension portion 95 d extending toward the rear side. Therefore, thecircuit board connection terminal 95 is able to be easily elasticallydeformed in the axial direction. Therefore, although inconsistencies inthickness of the circuit board 71 may occur due to manufacturingtolerances, an application of excessive force to the circuit board 71 inthe direction from the rear side to the front side of the circuit board71 is able to be prevented from occurring.

The first extension portion 95 b extends to the rear side of the circuitboard 71. The second connection portion 95 c extends from the firstextension portion 95 b toward the radially inner side. The secondextension portion 95 d extends from the second connection portion 95 ctoward the front side. Therefore, the second extension portion 95 d isconnected to the contact portion 95 e. Therefore, the circuit boardconnection terminal 95 is easily connected to the circuit board rearsurface 71 a.

The end of the front side of the second extension portion 95 d islocated at the rear side ahead of the end of the front side of the firstextension portion 95 b. Therefore, the circuit board is preferablylocated at the rear side ahead of a specific position in which thecircuit board connection terminal 95 is fixed to the connection terminalholding portion 64. As a result, the circuit board 71 is able to beeasily installed, and the circuit board connection terminal 95 is ableto be easily connected to the circuit board 71. In addition, force isable to be easily applied to the circuit board 71 in the direction fromthe rear side to the front side by the circuit board connection terminal95.

The circuit board connection terminal 95 preferably includes aplate-shaped contact portion 95 e. The contact surface 95 f contacts thecircuit board rear surface 71 a. Therefore, according to the presentpreferred embodiment, a contact region between the circuit boardconnection terminal 95 and the circuit board 71 is able to be enlargedin size, such that the circuit board connection terminal 95 and thecircuit board 71 is able to be stably fixed.

The first circuit board support portions 67 a and 67 b extend along thearrangement direction of the contact portion 95 e. That is, the firstcircuit board support portions 67 a and 67 b extend in the arrangementdirection of a specific portion in which force generated from thecircuit board connection terminal 95 is received through the contactportion 95 e in the circuit board 71. Therefore, according to thepresent preferred embodiment, the circuit board 71 is able to be morestably supported by the first circuit board support portions 67 a and 67b.

Two first circuit board support portions 67 a and 67 b are provided. Aportion of the first circuit board support portion 67 a are disposed atone side (−Y side) of the division-line direction of the plurality ofcontact portions 95 e. A portion of the first circuit board supportportion 67 b are located at the other side (+Y side) of thedivision-line direction of the plurality of contact portions 95 e.Therefore, by providing two first circuit board support portions 67 aand 67 b, the circuit board 71 is able to be stably supported. Inaddition, the first circuit board support portion 67 a and the firstcircuit board support portion 67 b may be spaced apart from each otherin the division-line direction. Therefore, the installation space of thesensor magnet 73 b is able to be increased in size. As a result, forexample, although the sensor magnet 73 b is easily increased in size(i.e., although the hall device is used as the rotation sensor 72), thesensor magnet 73 b is able to be easily disposed.

When viewed from the axial direction, the first protrusion portions 69 aand 69 b preferably overlap with at least a portion of the coilconnection portions 91 a-91 f in the circumferential direction. That is,the radial directional position of the deposition portion of the circuitboard 71 may be further shifted to the outside as necessary. Therefore,the region of a main surface of the circuit board 71 may be increased insize. In addition, when the circuit board 71 is arranged, the firstprotrusion portions 69 a and 69 b is able to be easily inserted into thenotch of the circuit board 71.

In addition, the following elements may also be applied to the presentpreferred embodiment.

The entirety of the first circuit board support portion 67 a may also bedisposed at one side (−Y side) of the plurality of contact portions 95 ein the division-line direction. In addition, the entirety of the firstcircuit board support portion 67 b may also be disposed at the otherside (+Y side) of the plurality of contact portions 95 e in thedivision-line direction.

As illustrated in FIG. 6, only one first circuit board support portionmay be used. Further, in the following description, the same componentsas those of the above-mentioned preferred embodiment are denoted withthe same reference numbers and therefore the description of thereof maybe omitted.

As illustrated in FIG. 6, the bus bar assembly 160 includes a bus barholder 161. The bus bar holder 161 preferably includes a single firstcircuit board support portion 167, a single second circuit board supportportion 67 c, two first protrusion portions 69 a and 69 b, two secondprotrusion portions 69 c and 69 d, and two bus bar holder convexportions 69 e and 69 f.

The first circuit board support portion 167 extends in the division-linedirection (Y-axis direction). As illustrated in FIGS. 3 and 5, the firstcircuit board support portion 167, for example, is provided in aspecific shape defined when the first circuit board support portion 67 ais connected to the first circuit board support portion 67 b along thedivision-line direction. Other elements of the first circuit boardsupport portion 167 are preferably identical to those of the firstcircuit board support portions 67 a and 67 b.

According to the above-mentioned structure, the circuit board 71 is ableto be more stably supported. In addition, a magnetoresistive elementthat reduces the size of the sensor magnet 73 b may be used as therotation sensor 72. Therefore, resolution of the rotation sensor 72 isable to be increased.

In the protrusion direction (X-axis direction) of the connector portion63, the first circuit board support portion 67 a may also be disposed ata position different from that of the first circuit board supportportion 67 b.

As illustrated in FIG. 7, the first circuit board support portion isdisposed at the holding portion rear surface 64 b of the connectionterminal holding portion 64. For example, the first circuit boardsupport portions 67 a and 67 b may also be disposed at any position ofthe first region AR1.

FIG. 7 is a plan view illustrating the bus bar assembly 260 according toanother example of a preferred embodiment of the present invention.Further, in the following description, the same components as those ofthe above-mentioned preferred embodiment are denoted with the samereference numbers and therefore the description of thereof may beomitted.

As illustrated in FIG. 7, the bus bar assembly 260 includes a bus barholder 261. The bus bar holder 261 preferably includes a single firstcircuit board support portion 267, a single second circuit board supportportion 67 c, two first protrusion portions 69 a and 69 b, two secondprotrusion portions 69 c and 69 d, and two bus bar holder convexportions 69 e and 69 f.

The first circuit board support portion 267 is disposed at the holdingportion rear surface 64 b. The first circuit board support portion 267extends in the division-line direction (Y-axis direction). Otherelements of the first circuit board support portion 267 are preferablyidentical to those of the first circuit board support portions 67 a and67 b shown in FIGS. 3 and 5, and the like.

In FIG. 7, only one first circuit board support portion 267 is provided.However, in this construction, a plurality of first circuit boardsupport portions may also be used.

Two or more second circuit board support portions 67 c may also be used.The second circuit board support portion 67 c may not be used.

Only one of the second protrusion portions 69 c and 69 d may be used ortwo second protrusion portions 69 c and 69 d may not be used. Only oneof the first protrusion portions 69 a and 69 b may be used or two firstprotrusion portions 69 a and 69 b may not be used.

The second protrusion portions 69 c and 69 d may not be deposited on thecircuit board 71. Likewise, the first protrusion portions 69 a and 69 bmay not be deposited on the circuit board 71.

In the above-mentioned description, although the circuit board 71 isdisposed at the rear side of the shaft 31, the present invention is notlimited thereto. Although the shaft 31 is inserted into a through-holeprovided to the circuit board 71, the shaft 31 may protrude toward therear side of the circuit board 71.

In so far as force is applied to the circuit board 71 from the rear sideto the front side, the structure of the circuit board connectionterminal 95 is not limited. For example, the structure of FIG. 8 mayalso define a structure of the circuit board connection terminal 95.FIG. 8 is a partially cross-sectional view illustrating some elements ofthe motor 310 according to another example of a preferred embodiment ofthe present invention. In the following description, the same componentsas those of the above-mentioned preferred embodiment are denoted withthe same reference numbers and therefore the description of thereof maybe omitted.

As illustrated in FIG. 8, the motor 310 includes a bus bar assembly 360.The bus bar assembly 360 preferably includes a wiring member 392. Thewiring member 392 includes a circuit board connection terminal 395. Thecircuit board connection terminal 395 preferably includes a firstconnection portion 395 a, a first extension portion 395 b, and a contactportion 395 c. The circuit board connection terminal 395 is differentfrom the circuit board connection terminal 95 in that only oneconnection portion and only one extension portion are provided.

The first connection portion 395 a protrudes from the holding portioninner surface 64 a toward the radially inner side. The first connectionportion 395 a is disposed at the radially outer side ahead of thecircuit board 71. The first extension portion 395 b extends from thefirst connection portion 395 a toward the rear side (+Z side). In moredetail, the first extension portion 395 b extends from the end of theradially inner side of the first connection portion 395 a toward therear side.

The contact portion 395 c extends from the end of the rear side (+Zside) of the first extension portion 395 b toward the radially innerside. The contact portion 395 c is disposed at the end of the radiallyinner side of the circuit board connection terminal 395. The contactportion 395 c preferably has a plate shape, and includes a contactsurface 395 d parallel or substantially parallel to the circuit boardrear surface 71 a at the front side (−Z side). The contact surface 395 dis preferably identical to the contact surface 95 f shown in FIG. 2.

Other elements of the contact portion 395 c are preferably identical tothose of the contact portion 95 e shown in FIG. 2. Other elements of themotor 310 are identical to those of the motor 10 shown in FIG. 1 and thelike.

According to the structure shown in FIG. 8, the circuit board connectionterminal 395 preferably includes only one connection portion and onlyone extension portion. Therefore, as compared to the shape of thecircuit board connection terminal 95, the shape of the circuit boardconnection terminal 395 is simplified. Therefore, according to thisstructure, the circuit board connection terminal 395 is able to beeasily manufactured.

The structure that increases the accuracy of positioning between therotation sensor 72 and the sensor magnet 73 b may also be disposed atthe circuit board 71. FIG. 9 is a partially enlarged cross-sectionalview illustrating the motor according to another example of a preferredembodiment of the present invention. Further, in the followingdescription, the same components as those of the above-mentionedpreferred embodiment are denoted with the same reference numbers andtherefore the description of thereof may be omitted.

The motor 410 preferably includes a circuit board 471. The circuit board471 includes a circuit board hole 471 c. The circuit board hole 471 c isdisposed at the center of plural circuit sensors 72 in the circuit board471.

The motor 410 includes a shaft 431. The shaft 431 includes a center hole431A at the end of the rear side (+Z side). The center hole 431A isconcaved from the end of the rear side (+Z side) of the shaft 431 towardthe front side (−Z side).

Before the first protrusion portions 69 a and 69 b and the secondprotrusion portions 69 c and 69 d are deposited, there is a highpossibility that the circuit board 471 easily move from a predeterminedposition. However, according to the above-mentioned structures ofpreferred embodiments of the present invention, the bus bar holderconvex portions 69 e and 69 f preferably are inserted into a holeportion disposed at the circuit board 71, as shown in FIG. 3. Therefore,movement of the circuit board 471 is able to be significantly reduced orprevented. In addition, positioning alignment between the circuit board471 and the shaft 431 becomes facilitated. As a result, the positioningaccuracy of the rotation sensor 72 attached to the circuit board 471,the shaft 431, and the sensor magnet 73 b rotationally disposed at theshaft 431 is able to be improved. According to the structure of FIG. 9,positioning between the circuit board 471 and the shaft 431 may bedetermined. As a result, the positioning accuracy between the rotationsensor 72 and the sensor magnet 73 b is able to be improved. In moredetail, according to the present preferred embodiment of FIG. 3, theposition of the circuit board 71 is preferably determined by the bus barholder 61. Therefore, the circuit board 71 includes a plurality ofelements disposed between the sensor magnet 73 b and the circuit board71. Meanwhile, according to the present preferred embodiment of FIG. 9,the circuit board 471 is fixed to the shaft 431. Therefore, the circuitboard 471 includes only the sensor magnet holding member 73 a disposedbetween the circuit board 471 and the sensor magnet 73 b. Therefore, thestructure of the preferred embodiment shown in FIG. 9 is able to reduceto a greater degree the errors generated in the manufacturing process ofthe motor 10, resulting in increased positioning accuracy.

In the present preferred embodiment of FIG. 9, the inner diameter of thecircuit board hole 471 c is preferably identical or substantiallyidentical to the inner diameter of the center hole 431A. A jig havingboth an inner diameter of the circuit board hole 471 c and an outerdiameter identical or substantially identical to an inner diameter ofthe center hole 431A is inserted into the circuit board hole 471 c andthe center hole 431A. As a result, the circuit board 471 and the shaft431 may perform higher-accuracy positioning. Therefore, the positionaccuracy between the rotation sensor 72 and the sensor magnet 73 b isimproved, and the accuracy of position detection of the rotation sensoris improved. The center hole 431 is generally a center hole formed whena bar-shaped member is fabricated. Therefore, the shaft 431 need not beespecially fabricated, and a conventional shaft structure can be used.

The structure that increases the accuracy of positioning between therotation sensor 72 and the sensor magnet 73 b is not limited thereto. Inthe above-mentioned structures of preferred embodiments of the presentinvention, the plurality of rotation sensors 72 (e.g., a hall sensor)may be provided with a circular or substantially circular shape on thecircuit board. Therefore, the accuracy of positioning between therotation sensor 72 and the sensor magnet 73 b is able to be increased.For example, in the case where the rotation sensor 73 b (e.g., MRsensor) is disposed at the center axis on the circuit board, theexternal appearance of the shaft may be used or the structure of usingthe bearing may also be used.

Features of the above-described preferred embodiments and themodifications thereof may be combined appropriately as long as noconflict arises.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

What is claimed is:
 1. A motor, comprising: a rotor including a shaftwith a center on a center axis extending in one direction; a statorenclosing the rotor and rotating the rotor about the center axis; afirst bearing located at a first side in the one direction of the statorand supporting the shaft; a second bearing located at a second sideopposite to the first side of the stator and supporting the shaft; acylindrical housing holding the stator and the first bearing; a bus barassembly holding the second bearing, and allowing an end of the firstside to be located in the housing; a cover fixed to the housing to coverat least a portion of the second side of the bus bar assembly; a circuitboard disposed between the second bearing and the cover in the onedirection, and allowing a surface of the second side to cross the onedirection; wherein the bus bar assembly includes: a bus bar electricallyconnected to the stator; a wiring member electrically connecting anexternal power supply to the circuit board; and a bus bar holder holdingthe bus bar and the wiring member; the bus bar holder includes: acylindrical main body portion including an opening at the second side; aconnector portion protruding from the main body portion toward aradially outer side of the center axis; a bottom portion widening froman inner surface of the main body portion toward a radially inner side;and a first circuit board support portion extending from the bottomportion toward the second inner side, and supporting the circuit boardfrom the first side; the cover covers the second side of the opening;the wiring member includes: an external power-supply connection terminalprovided to the connector portion to be electrically connected to theexternal power-supply; and a circuit board connection terminalelectrically connected to the circuit board; the circuit boardconnection terminal includes a contact portion connected to the circuitboard, and applies force to the circuit board through the contactportion in a direction from the second side to the first side; the firstcircuit board support portion is disposed at a region of the bottomportion to define a side at which the circuit board connection terminalis located when viewed from the one direction; and the first circuitboard support portion and the contact portion are disposed at differentpositions when viewed from the one direction.
 2. The motor of claim 1,wherein the bus bar holder includes a second circuit board supportportion that extends from the bottom portion to the second side tosupport the circuit board from the first side; and the second circuitboard support portion is disposed at a region of the bottom portion todefine a side opposite to a specific side at which the circuit boardconnection terminal is located when viewed from the one direction. 3.The motor of claim 1, wherein the first circuit board support portion isdisposed between the shaft and the contact portion in a radialdirection.
 4. The motor of claim 3, wherein the bus bar holder includesa third circuit board support portion that supports the circuit boardfrom the second side; and the third circuit board support portion isdisposed at a region of the bottom portion to define a side opposite toa specific side at which the circuit board connection terminal islocated when viewed from the one direction.
 5. The motor of claim 4,wherein the third circuit board support portion is deposited at asurface of the second side of the circuit board.
 6. The motor of claim1, wherein the circuit board connection terminal includes: a firstconnection portion extending from a connection terminal holding portionprovided at the inner surface of the main body portion toward theradially inner side; and a first extension portion extending from thefirst connection portion toward the second side.
 7. The motor of claim6, wherein the circuit board connection terminal includes: a secondconnection portion extending from the first extension portion in theradial direction; and a second extension portion extending from thesecond connection portion in the one direction.
 8. The motor of claim 7,wherein the first extension portion extends to the second side of thecircuit board; the second connection portion extends from the firstextension portion toward the radially inner side; and the secondextension portion extends from the second connection portion toward thefirst side, and is connected to the contact portion.
 9. The motor ofclaim 8, wherein an end of the first side of the second extensionportion is located at the second side ahead of an end of the first sideof the first extension portion.
 10. The motor of claim 1, wherein thecontact portion has a plate shape and includes a contact surfaceparallel or substantially parallel to a surface of the second side ofthe circuit board; and the contact surface contacts the surface of thesecond side of the circuit board.
 11. The motor of claim 1, wherein thebus bar assembly includes a plurality of the wiring members; the contactportion of the circuit board connection terminal in the plurality ofwiring members is provided in a predetermined direction within a surfaceof the second side of the circuit board; and the first circuit boardsupport portion extends in the predetermined direction.
 12. The motor ofclaim 1, wherein the bus bar assembly includes the plurality of wiringmembers; the contact portion of the circuit board connection terminal inthe plurality of wiring members is provided in a predetermined directionwithin a surface of the second side of the circuit board; the bus barholder includes two second circuit board support portions; at least aportion of one first circuit board support portion is located at oneside of the plurality of contact portions in the predetermineddirection; and at least a portion of the other first circuit boardsupport portion is located at the other side of the plurality of contactportions in the predetermined direction.